Bump peter-evans/create-pull-request from 7 to 8 (#871)

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 7 to 8.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](peter-evans/create-pull-request@v7...v8)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/create_release_pr.yaml

@@ -52,7 +52,7 @@ jobs:
       # See: https://github.com/peter-evans/create-pull-request/tree/master#reference-example
       - name: create PR
         id: create_pull_request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@v8
         with:
           # See: https://github.com/peter-evans/create-pull-request/blob/master/docs/concepts-guidelines.md#triggering-further-workflow-runs
           # See: https://github.com/peter-evans/create-pull-request/issues/48#issuecomment-537478081

.github/workflows/dart_deps.yaml

@@ -29,7 +29,7 @@ jobs:
       # See: https://github.com/peter-evans/create-pull-request/tree/master#reference-example
       - name: create PR
         id: create_pull_request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@v8
         with:
           token: ${{ secrets.PAT }} # See: https://github.com/peter-evans/create-pull-request/blob/master/docs/concepts-guidelines.md#triggering-further-workflow-runs
           # See: https://github.com/peter-evans/create-pull-request/issues/593